This invention relates to an endoscope wherein the flexibility of a part of signal wires, inserted through the insertable part, is varied.
Recently, there has come to be extensively used an endoscope (scope or fiber scope) whereby organs within a body cavity and the like can be diagnosed or inspected by inserting an elongate insertable part into the body cavity.
It is used not only for medical uses but also for industrial uses in observing and inspecting objects such as boilers, machines and interiors of pipes and machines of chemical plants.
Further, there are used various kinds of electronic scopes wherein a solid state imaging device as a charge coupled device (CCD) is used as an imaging means. The electronic scope advantages are that the resolution is higher and it is easier to record, reproduce, enlarge and compare picture images than in a fiber scope.
On the signal wire, connected to the solid state imaging device and transmitting driving signals or output signals, a shielding technique as a countermeasure of reducing emitted noises is disclosed in the publications of Japanese patent application publication No. 42610/1987 and Japanese patent application laid open No. 83640/1985.
In the publication of the above mentioned Japanese patent application publication No. 42610/1987, a signal wire from a solid state imaging device contained in an X-ray shielding body made of a metal is coated with a shielding wire which is electrically connected to the X-ray shielding body to prevent defects such as an operation failure and picture image disturbance from being caused even under the sight with X-rays. In the publication of the above mentioned Japanese patent laid open No. 83640/1985, a signal wire is shielded to prevent picture image noises when using a high frequency treating tool.
Now, shielding the entire signal wire is advantageous not only to the above but also to preventing noises emitted from the signal wire. In order to further elevate this preventing effect, it is effective to elevate the shielding density. However, if the shielding density is made high, the rigidity of the signal wire will become high and the curving operation of the endoscope insertable part through which this signal wire high in rigidity is inserted will be obstructed. On the other hand, if the shielding density is made low to improve the curving operability, noises will not be able to be prevented from being mixed in or discharged out.